The present invention relates to a recording apparatus which employs, for example, a circulating recording scheme, and more particularly, to a recording apparatus, a recording method, and a recording medium storing a program therefor for effectively recovering recorded contents from errors which have occurred therein.
Time-series video and audio data have been recorded by a recording apparatus. Since such a recording apparatus has a limited memory capacity, a circulating recording scheme is employed. The circulating recording scheme, which circularly utilizes a limited memory area reserved in a recording apparatus, sequentially overwrites the oldest data in time series with the most recent data, thereby making it possible to preserve a predetermined amount of past data for reproduction.
In an example of a remote monitoring system which utilizes a video storage/delivery system, time-series video data sequentially captured by an image pickup apparatus such as a web camera is recorded (stored) on a large-capacity recording medium such as a magnetic disk (for example, a hard disk drive), an optical disk, a semiconductor memory or the like, and the recorded video data is delivered as required to a user through a network, thereby allowing the user to monitor the image on a monitor screen installed at a remote location. In addition, a plurality of image pickup apparatuses may be installed to monitor images at a plurality of locations (images on a plurality of channels).
When time-series video and audio data are recorded by a recording apparatus, image frames are compressed, for example, in accordance with an image compression scheme such as JPEG before the data is recorded. However, when the image frames are compressed, the data size can differ from one frame to another depending on image conditions.
For this reason, in a circulating recording apparatus which circularly uses a memory area reserved in the recording apparatus, given as an example of the prior art, investigations are now under way to edit time-series input data into data blocks of a predetermined size, each comprised of a plurality of sub-blocks, and write the data in data blocks, and to read data from the recording apparatus to a cache memory in sub-blocks in response to a request for outputting particular data to selectively output the particular data included in some sub-block (see, for example, US Patent Application Publication No. US2005/0076176A1). This strategy is intended to improve the efficiency of accessing the circulating recording area to effectively utilize the circulating recording area.